Field of the Invention
The present invention relates to image forming apparatuses such as color laser printers and color copiers, and optical sensors used in the image forming apparatuses and the like.
Description of the Related Art
An image forming apparatus performs misregistration correction control and density correction control in order to maintain the quality of an image to be formed. In order to perform these types of correction control, the image forming apparatus forms a detection image on an image carrier, and detects the detection image by using a reflection type optical sensor including one light-emitting element and two light-receiving elements. For example, Japanese Patent Laid-Open No. 2006-251686 discloses a configuration in which the same optical sensor is used in the misregistration correction control and the density correction control.
Also, the image forming apparatus forms an image on a recording material while conveying the recording material. Furthermore, the image forming apparatus includes members such as an intermediate transfer belt that are rotationally driven for forming images. The image forming apparatus also performs control such that the speed of a member that is conveyed or rotated at a predetermined speed is detected, and the fluctuation of the speed is suppressed. Accordingly, as a result of not only performing the misregistration correction control and the density correction control, but also detecting, with a common optical sensor, the speed, speed fluctuation, or the like of a member or the like that is conveyed or rotationally driven, the number of components can be reduced. Furthermore, in order to improve accuracy in each control, accuracy in detecting a misregistration amount, density, speed, and speed fluctuation that are detected by using the optical sensor needs to be improved. That is, detection accuracy of a target such as the detection image needs to be improved.